Thru-hull hose sizing

[DHV90]

Hi guys,

Im replacing all the hoses soon, and my spigots are all odd sizes, e/g a 24mm in a few places, the bead at the end might be 25mm but the length of the spigot is noticeably less than 25mm, so 25mm hose wouldnt work, but 19mm seems like a big step down.
Is it right to go for the next size down (19mm in this case) and squeeze it on or is 24-19mm too far? Any input appreciated!

The spigots on the engine water feed are also all 15mm, too small for 16mm hose, so is nearest size down the best rule? Theyll all be double clamped with mikalor clamps FWIW

 

[CCJ]

Hi guys,

Im replacing all the hoses soon, and my spigots are all odd sizes, e/g a 24mm in a few places, the bead at the end might be 25mm but the length of the spigot is noticeably less than 25mm, so 25mm hose wouldnt work, but 19mm seems like a big step down.
Is it right to go for the next size down (19mm in this case) and squeeze it on or is 24-19mm too far? Any input appreciated!

The spigots on the engine water feed are also all 15mm, too small for 16mm hose, so is nearest size down the best rule? Theyll all be double clamped with mikalor clamps FWIW

what is the I/D of your existing hoses

 

[DHV90]

old hoses are long gone!

 

[Plum]

Hi guys,

Im replacing all the hoses soon, and my spigots are all odd sizes, e/g a 24mm in a few places, the bead at the end might be 25mm but the length of the spigot is noticeably less than 25mm, so 25mm hose wouldnt work, but 19mm seems like a big step down.
Is it right to go for the next size down (19mm in this case) and squeeze it on or is 24-19mm too far? Any input appreciated!

The spigots on the engine water feed are also all 15mm, too small for 16mm hose, so is nearest size down the best rule? Theyll all be double clamped with mikalor clamps FWIW

I have had no problems in contracting hose by a mm in diameter using good quality hose clips as long as you use suitable hose. The spiral reinforced pvc hose typically stocked by chandlers is very difficult to squash but the clear pvc hose that has braided fibre reinforcement is better and in my experience does work on the suction side of a seawater pump. If you are connecting to any hot parts of an engine then reinforced black rubber collant/ heater hose is easy to squash down. The easiest of all hose to squash down a bit is silicone hose, available in both fibre and wire reinforced, but is more expensive.

Www.solocoastalsailing.co.uk

 

[lpdsn]

Everything should be BSP even if it is a continental-built boat with dimensions expressed in mm. You can usually get smaller hose onto a next-size-up fitting by soaking it in hot water, using washing up liquid as a lubricant and only skinning two or three knuckles. Make sure you have a swear box handy.

 

[LittleSister]

so 25mm hose wouldnt work, but 19mm seems like a big step down.
Is it right to go for the next size down (19mm in this case) and squeeze it on or is 24-19mm too far? Any input appreciated!

The next size down is not 19mm but 22mm (see https://www.asap-supplies.com/hose/coolant-heater-hose for instance), or 7/8" in old money.

I had an engine inlet that (if I remember it all the right way round) was bodged with a 1" (25mm) hose that was obviously too loose and leaking, but 3/4" (19mm) was too small to get on. The other end of the hose was a 1" to 3/4" fitting inserted in a strainer with a 3/4" outlet. I bought a 3/4" to 7/8" adapter fitting for that end, and some 22mm hose. Job done.

 

[DHV90]

The next size down is not 19mm but 22mm (see https://www.asap-supplies.com/hose/coolant-heater-hose for instance), or 7/8" in old money.

I had an engine inlet that (if I remember it all the right way round) was bodged with a 1" (25mm) hose that was obviously too loose and leaking, but 3/4" (19mm) was too small to get on. The other end of the hose was a 1" to 3/4" fitting inserted in a strainer with a 3/4" outlet. I bought a 3/4" to 7/8" adapter fitting for that end, and some 22mm hose. Job done.

Thats really useful, thanks for that, I wont risk going too big.

If its any use, this is the details of the seacocks:

http://www.impala28.co.uk/wp-content/uploads/2011/03/Elancoseal-sheet.gif

and it does suggest that it's intended for 3/4 hose which is really confusing me. I might order a small piece of 3/4 and see if it will stretch on as a test

 

[Tranona]

It is often a struggle to get hoses onto barbed spigots like that, particularly the larger ones. You need to warm the hose either with a hot air gun or boiling water and lubricate the spigot with washing up liquid and gradually work it onto the spigot. once it is on it will shrink and the clip is almost redundant. If you want to remove it in the future you may well have to cut it off!